Pebble does have its supporters, including Graedel. The US is currently a net importer of the minerals that would be mined at Pebble, he says. If we choose not to develop it, he says, “then I think that means we are saying that we would like those sorts of mines to be developed somewhere else, probably where the controls would be less stringent than they would be if a mine were developed in the US.” Graedel would like to see the mine opened, but with the strongest possible protections in place.

Seal is less certain. Mines are unique, he says, because “you are kind of stuck with building it wherever you find the ore deposit, and they are very rare, globally speaking.” But that often brings mines in conflict with other valuable resources, like world-class fisheries, he says. “The question is, can we have both?” At Pebble, Seal says, the answer requires carefully analyzing the environmental impacts of the mine’s proposal — and potential alternatives — which won’t be possible until Pebble formalizes its plan. “I don’t know what the right answer is at this point,” Seal says.

Speaking at a breakfast meeting of the Resource Development Council for Alaska last month, Pebble CEO Tom Collier announced preliminary plans for what he said would be a smaller, safer mine. Collier said that the company had made numerous changes in response to concerns, including abandoning the use of cyanide to recover a portion of the gold and building a sturdier tailings dam.

Collier also announced that the mine would scale back dramatically, targeting just a fraction of the deposit. The new plan calls for a 5.4-square-mile footprint, down from an estimated 13 square miles, and requires just one of three proposed tailings facilities, limiting its impact to a single tributary of one of nine major rivers that drain into Bristol Bay. (The company has decided not to pursue dry stacking, because it would increase the mine’s footprint, according to a spokesperson.)

But the mine’s opponents remain unconvinced. According to the EPA’s 2014 assessment, which formed the basis for its restrictions, even a small mine would have significant and irreversible impacts on wetlands, rivers, and fish, says Heimer of the NRDC. And she suspects that the new plan is just a foot in the door—a first step toward exploiting the larger potential of the deposit, which Pebble’s backers continue to tout to investors.

Any day now, the EPA will announce whether or not it will lift its restrictions. Pebble will have 30 months to submit an application for a permit and begin seeking regulatory approval—but the fight won’t be over. Alaska voters are pushing a ballot initiative that would require the state department of fish and game to grant permits for any project that could affect salmon habitat. And the mine has amassed many high-profile critics over the years. Dozens of jewelers — including Tiffany and Co. — have signed a pledge not to buy gold from Pebble.